Kinetics of Alloantigen-Specific Regulatory CD4 T Cell Development and Tissue Distribution After Donor-Specific Transfusion and Costimulatory Blockade

Abstract

BackgroundThe influence of donor-side regulation toward recipient antigens on graft outcome is poorly understood.MethodsBecause this influence might be due in part to the accumulation of tissue-resident memory T cells in the donor organ, we used a standard murine tolerization model (donor-specific transfusion plus CD40L blockade) to determine the kinetics of development and peripheralization of allospecific regulatory T cell in lymphoid tissues and liver, a secondary lymphoid organ used in transplantation.ResultsWe found that donor-specific transfusion and CD40L blockade leads to a progressive and sustained T regulatory allospecific response. The cytokines IL10, TGFβ, and IL35 all contributed to the regulatory phenomenon as determined by trans vivo delayed hypersensitivity assay. Unexpectedly, an early and transient self-specific regulatory response was found as well. Using double reporter mice (forkhead box p 3 [Foxp3]-yellow fluorescent protein, Epstein-Barr virus-induced gene 3 [Ebi3]-TdTomRed), we found an increase in Foxp3+CD25+ regulatory T (Treg) cells paralleling the regulatory response. The Ebi3+ CD4 T cells (IL35-producing) were mainly classic Treg cells (Foxp3+CD25+), whereas TGFβ+ CD4 T cells are mostly Foxp3-negative, suggesting 2 different CD4 Treg cell subsets. Liver-resident TGFβ+ CD4 T cells appeared more rapidly than Ebi3-producing T cells, whereas at later timepoints, the Ebi3 response predominated both in lymphoid tissues and liver.ConclusionsThe timing of appearance of donor organ resident Treg cell subsets should be considered in experiments testing the role of bidirectional regulation in transplant tolerance.

Operational immune tolerance towards transplanted allogeneic pancreatic islets in mice and a non-human primate

“…Interestingly, this in vivo immune regulation/tolerance was dependent on IL-10, TGF-β and IL-35, thereby suggesting a prominent involvement of various subsets of T regulatory cells (Treg) in the observed peripheral immune hyporesponsiveness by the recipient towards the specific donor. A similar pattern of peripheral immune regulation has previously been described in humans and Rhesus monkey due to tolerance to non-inherited maternal antigens [44], as well as in B6 mice made tolerant by donorspecific transfusion plus costimulation blockade [44,45]. Importantly, while the recipient baboon's recall response to TT/D was significantly reduced in the presence of the islet [1] and Ctrl Ag [2]; n = 1 each).…”

Treg-Cell-Derived IL-35-Coated Extracellular Vesicles Promote Infectious Tolerance

“…A standard approach for inducing peripheral allograft tolerance in mice is the transfusion of splenocytes from one strain into another, followed by treatment with anti-CD154 monoclonal antibody (mAb) (MR-1). Indefinite allograft survival across major histocompatibility complex (MHC) and minor H mismatches is induced in the first week, yet the full maturation of the alloantigen-specific Treg cell response appears to require an active process lasting 4-5 weeks (Tomita et al, 2016). This process occurs in distinct phases.…”

“…However, by day 7, newly arising alloantigen-specific T cells are directed toward anergy rather than a Treg cell fate (Burrell and Bromberg, 2012). By day 14, a mixture of self-specific and allo-specific regulation in spleen and lymph nodes can be detected, and by day 35, the self-reactive component of Treg cell suppression has disappeared, and a purely allo-specific regulation pattern emerges that is stable until at least day 70 (Tomita et al, 2016). Alloantigen-specific T cells were shown by tetramer staining on day 30 to be enriched in Treg cells (Young et al, 2018), and the latter were found to be distributed in both lymphoid and non-lymphoid (e.g., liver) tissue compartments (Tomita et al, 2016).…”

“…By day 14, a mixture of self-specific and allo-specific regulation in spleen and lymph nodes can be detected, and by day 35, the self-reactive component of Treg cell suppression has disappeared, and a purely allo-specific regulation pattern emerges that is stable until at least day 70 (Tomita et al, 2016). Alloantigen-specific T cells were shown by tetramer staining on day 30 to be enriched in Treg cells (Young et al, 2018), and the latter were found to be distributed in both lymphoid and non-lymphoid (e.g., liver) tissue compartments (Tomita et al, 2016). Due to our interest in the disproportionate effects of the small number of Treg cells in non-lymphoid tissues (kidney, liver, lungs, and heart) routinely used in organ transplantation, we wished to determine how relatively few Treg cells at these sites could have such a powerful immunosuppressive impact (Jankowska-Gan et al, 2012;Sullivan et al, 2014Sullivan et al, , 2017Olson et al, 2013).…”

Donor HLA−DR Drives the Development of De Novo Autoimmunity Following Lung and Heart Transplantation

“…While all 7 patients in our study developed a response to the donor (DR15)−specific ColV peptide post-transplant, 4/7 also developed regulation of this response by either TGF−β (conventional) and IL−35 (EV−based 21 ) cytokines, or both. The role of IL−35 in regulation was previously reported in monkey, 30 human, 31 and mouse 32 immune tolerance studies. Thus, the present report documents a major EV influence on both antigen presentation (DR15 acquisition from the graft by host DC) and regulatory T function (IL−35 “exokine”) in clinical transplantation.…”